Evaluation of a Novel Thermal Accelerant for Augmentation of Microwave Energy during Image-guided Tumor Ablation

Abstract

The primary challenge in thermal ablation of liver tumors (e.g. hepatocellular carcinoma and hepatic colorectal cancer) is the relatively high recurrence rate (~30%) for which incomplete ablation at the periphery of the tumor is the most common reason. In an attempt to overcome this, we have developed a novel thermal accelerant (TA) agent capable of augmenting microwave energy from a distance normally unattainable by a single microwave ablation antenna. This cesium-based block co-polymer compound transforms from a liquid to a gel at body temperature and is intrinsically visible by computed tomography. Using an agarose phantom model, herein we demonstrate that both the rate and magnitude of temperature increase during microwave ablation were significantly greater in the presence of TA when compared with controls. These results suggest robust augmentation of microwave energy, and may translate into larger ablation zone volumes within biologic tissues. Further work using in vivo techniques is necessary to confirm these findings.

The in vivo performance of a novel thermal accelerant agent used for augmentation of microwave energy delivery within biologic tissues during image-guided thermal ablation: a porcine study

“…In zone 2, the nuclear smearing observed within zone 1 was again present but appeared less obvious at greater distances from the antenna, concordant with the exponential decay in energy observed in prior in vitro trials [18]. Using this finding as a surrogate for microwave-induced cytotoxicity, the histologic changes in zone 2 also appeared to derive from both direct (microwave) and indirect (thermal conduction) mechanisms, as in zone 1.…”

“…As previously described [18], non-radioactive caesium chloride (CsCl; Sigma-Aldrich, St. Louis, MO) and a polyethylene glycol-based reverse phase-transition block-co-polymer (AK88; Akina Inc., West Lafayette, IN) were used to prepare the thermal accelerant. The polymer (200 mg) was mixed with a solution of 100-250 mg CsCl in 0.5 ml doubly distilled, deionised water.…”

“…In an attempt to mitigate these factors and improve treatment outcomes, we have created a novel agent intended to enhance the transmission of microwave energy within biologic tissues and generate larger ablation zones through an increase in the total volume of cytotoxic thermal energy. Preliminary results from an in vitro evaluation of this thermal accelerant (TA) have been previously published [18] and demonstrated a more rapid increase in temperature beyond the cytotoxic threshold when compared with controls, a finding that was sustained over the entirety of the observed ablation period. Herein, we describe the results of in vivo ablation trials in swine with the hypothesis that TA administration will increase ablation zone volumes following microwave ablation in two different tissue types, and that the magnitude of this effect will correlate with the rate of blood flow to those tissues.…”

Cancer cell membrane-modified biodegradable mesoporous silica nanocarriers for berberine therapy of liver cancer

“…Liver cancer is one of the most common tumors with an extreme mortality rate of about 600 000 people per year globally according to the World Health Organization. [1][2][3][4] Clinically, chemotherapy is commonly used as the standard treatment for patients aer surgery and some patients with unresectable liver cancer. However, traditional chemotherapeutic drugs possess high cytotoxicity to normal tissues and entail some limitations, including drug resistance and lack of specicity.…”

2450-MHz microwave ablation temperature simulation using temperature-dependence feedback of characteristic parameters

“…In the clinical MWA, 915‐ and 2450‐MHz MWAs are usually used to obtain desired thermal coagulation by constant powers such as 40, 50, and 60 W. Compared with surgical resections, MWA has fewer complications and minimally invasive advantages . Many studies show that complete coagulation can occur instantly at least 55‐60°C . In the treatment of liver tumors, the zone with the temperature higher than 54°C is considered as thermal coagulation zone .…”